Nebulizer with auxiliary gas input

ABSTRACT

A nebulizer has a mixing chamber into which is projected a high velocity jet of oxygen that aspirates water from a container connected with the mixing chamber. A compressed air input port in the chamber projects a stream of compressed air adjacent to and alongside the oxygen jet to impinge upon the tapered entrance surface of a venturi tube that forms an exit from the mixing chamber. The percentage of oxygen in the output is effectively rendered independent of output back pressure, the lower limit of the amount of oxygen in the output is lowered, the amount of water entrained in the output is increased, and the amount of waste water is decreased.

This application is a continuation-in-part of my prior application forNebulizer, Ser. No. 661,149, filed Oct. 15, 1984, now U.S. Pat. No.4,629,590 issued 3-17-87 and assigned to the assignee of the presentapplication.

BACKGROUND OF THE INVENTION

The present invention relates to nebulizers for inhalation therapy. Itmore particularly concerns a nebulizer having improved moisturizingcapability with a wider range of oxygen percentage and lesssusceptibility to variation of back pressure.

In common forms of inhalation therapy, oxygen or an oxygen enrichedmixture of air is provided for introduction to a patient's lungs bymeans of suitable breathing apparatus. The gas mixture is preferablymoisturized and transmitted to the patient through a flexible tube whichmay be several feet or more in length. Particularly where such a tube iscorrugated, but even where it is not, water in the moisturized gasmixture tends to drop out of the mixture, collecting in lower portionsor bends of the connecting conduit. The water collected in the conduitmay increase in volume to a point where the connecting conduit is eitherpartially or entirely blocked, thereby greatly endangering the patientby obstruction of the supply of breathable gas.

The nebulizer provides a gas stream that entrains water particles ratherthan water vapor (as in a humidifier). It requires a minimum waterparticle size because it must insure that water particles will reachdeeper portions of the respiratory tract. In a humidifier the gascarries water vapor rather than water particles and the moisture in theinhaled mixture may be absorbed before it reaches deeper portions of therespiratory tract. In the nebulizer, liquid particle size preferably isfrom about five microns down to about two microns. Particles larger thanfive microns have a greatly increased tendency to drop out of themixture during flow from the nebulizer to the patient. It is these largesize particles that must be avoided. Thus, large particles in themixture do no good to the patient because they generally do not remainin the mixture for time long enough to reach the patient. But moreimportantly, they tend to collect and fully or partially occlude theconnecting tubing, requiring frequent attention and draining of thetubing to avoid complete blocking of flow.

Prior attempts to remove larger droplets from the inhalation mixture arebasically ineffective, inefficient, complex, and costly. For example,the U.S. Pat. No. to Cronenberg, 4,243,396, describes a tortuous spiralpath formed between a pair of telescoping tubes as a separator of gasdroplets. The U.S. Pat. No. to Kienholz et al, 4,267,974, describes achamber which is termed a baffling chamber having a baffle plate at thechamber exit. The U.S. Pat. No. to Schwartz et al, 4,177,945, shows atortuous path that results in turbulent flow for removal of liquiddroplets. These arrangements are largely ineffective, greatlycomplicating nebulizer structure, thereby increasing costs andcompromising efficiency.

Prior nebulizers have other problems, such as limited range of oxygencontent of the output mixture and sensitivity to back pressure, whichderive from the nature of their use and operational structure.

A nebulizer is used to provide a gas mixture that may be selectivelyvaried from a high oxygen content to as little as 28% oxygen. Thus, thenebulizer is often provided with an adjustable air intake through whichselectively varying amounts of air are admitted to the mixing chamberfor mixing with the pure oxygen that is supplied under pressure.

Because air is generally drawn into the mixing chamber of the nebulizerby venturi action of a high-velocity oxygen stream, which provides thelow pressure for drawing the air in, the minimum amount of oxygenpercentage in the outgoing mixture is limited. Air itself has an oxygencontent of about 21%, and thus it is not possible, by the negativepressure of venturi action of a stream of pure oxygen, to draw in enoughair to obtain an oxygen content in the output of the nebulizer below28%, as is often required or desired. Many nebulizers are not capable ofproviding an outgoing mixture having an oxygen content of less thanabout 35%, and oxygen content of less than about 28% has been availablepreviously only with expensive and complex additional regulatingequipment.

Normally, a nebulizer is adjusted to provide a desired predeterminedoxygen flow rate, such as, for example, in the order of about fiveliters per minute, to thereby provide a desired output flow rate of themoisturized oxygen-enriched inhalation mixture of 28% oxygen. However,back pressure of various devices, including the patient mask and hosesinterconnected between the mask and the nebulizer, will cause variationof the air entrainment input flow rate from a desired value, which, inturn, causes variation in the percentage of oxygen in the outputmixture. Thus, outputs of prior nebulizers have been difficult toprecisely control. Still further, the large droplets of water which fallout in the tubing connecting the nebulizer with the patient are waste,in addition to providing undesirable collections of water in the tubing,and generally indicate an inefficiency of complete utilization of thesterile water that is used.

Accordingly, it is an object of the present invention to provide anebulizer that avoids or minimizes above mentioned disadvantages.

SUMMARY OF THE INVENTION

In carrying out principles of the present invention in accordance with apreferred embodiment thereof, a nebulizer for producing an outputmixture of oxygen-enriched air and water for inhalation therapycomprises a container confining a body of liquid, a mixer body mountedto the container and defining a mixing chamber having a first inputport, a nozzle in the chamber for projecting a first stream of gas athigh velocity from the input port to the container, and aspirating meansconnected between a lower portion of the container and a point adjacentthe nozzle for flowing water from the container to the gas stream. Asecond input port is provided in the chamber for projecting a secondstream of a second gas toward the first stream to produce a combinedstream comprising a mixture of water and gas from both of the inputports. More specifically, oxygen is projected as a first stream througha high velocity nozzle to entrain water from the container and to flowat high velocity through a venturi tube which couples the mixing chamberto an upper portion of the container, above the water confined therein.Compressed air is projected as a second gas into the chamber from thesecond input port and caused to flow alongside the high velocity oxygenstream and also toward the venturi. This compressed air stream impingesupon the inclined entrance surface of the venturi tube to provideimproved mixing action.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial illustration, with parts broken away, of a unitarynebulizer assembly incorporating features of the present invention;

FIG. 2 is a section taken on line 2--2 of FIG. 3;

FIG. 3 is a longitudinal section of the nebulizer taken on line 3--3 ofFIG. 2;

FIG. 4 is a section taken on line 4--4 of FIG. 3;

FIG. 5 is a vertical sectional view illustrating interaction of the twogas streams;

FIG. 6 is a horizontal sectional view showing the top of the venturitube entrance surface and the flow of the gas-water mixture; and

FIG. 7 is a sectional view of the heater taken on line 7--7 of FIG. 2.

DETAILED DESCRIPTION

Shown in FIGS. 1 and 3 is a container 10 having a truncated conical wall12 and a closed bottom 14 confining a body of liquid, such as sterilizedwater or a saline solution 16, filling the container to a point wellbelow its upper edge. A lid 18 is fixed to and seals the open upper endsof the container and is molded integrally with a circular tubularmixture body 20 including a generally upstanding circular tubular wall22 that extends from an opening 24 in the lid upwardly to a body cap 26to which is secured an input fitting 28 connected to an input oxygenhose 30. Fixed to the cap 26, in line with the input passage 32 of thefitting 28, is a nozzle 34 having a nozzle discharge orifice 36 ofdecreased diameter, whereby the nozzle will project the incoming gas athigh velocity into a mixing chamber 40 defined within the tubular mixerbody 20. Mounted to and depending from the cap 26 is a liquid aspiratingfitting 42 connected by means of a tube 44 to a lower portion of thecontainer whereby the increased velocity gas projected from nozzleorifice 36 will provide a decreased pressure within the chamber atfitting 42 to draw liquid from the container to be mixed with theprojected gas stream. Much of the liquid thus entrained within theincreased velocity gas stream is in the form of water droplets, but manysuch droplets will be larger than the maximum desirable droplet size(about 5 microns).

Fixed to an depending from the cap 26, and also fixed to the exterior ofnozzle 34 is a channel shaped baffle or air deflector 46 having firstand second side walls 48,50 (FIG. 2) interconnected by a web 52 fixed tothe body of nozzle 34. Wall 48 is significantly larger than wall 50,extending further from web 52 for reasons to be explained below. Thelower end of deflector 46 extends somewhat below the orifice 36 andbelow the aspirating fitting 42.

A second gas input port in an upper portion of tubular wall 22 isdefined by a fitting 54 sealed to wall 22 and having an axis normal tothe axis of the circular wall 22 and directed at deflector web 52 at apoint above nozzle orifice 36. The upper end of mixer body 20 iscompletely closed and sealed, except for the two gas input ports.Fitting 54 is connected via a hose 56 to a source of compressed air (notshown) to feed a stream of air to deflector 46. The latter redirects theair stream downwardly alongside the oxygen stream from nozzle 34 andalong an axis substantially parallel to the axis of the oxygen streambut slightly skewed relative to the axis of the oxygen stream by virtueof the relatively extended deflector side wall 48. Thus the compressedair stream is directed downwardly with a component of circular motion.The mixer body is formed with an elbow conduit 64 having a horizontallydirected nebulizer discharge or output leg 66 and a vertically directedleg 68 extending through the lid 18 into communication with the upperportion of container 10.

A mixture venturi tube 70 is fixed to and aligned with the tubular wall22, extending downwardly therefrom in axial alignment with the inputpassage 32 and the axis of jet nozzle 34, through the lid 18, throughthe open end of mixer body 20, and terminating at an end 72 below thelid but adjacent the top of the container. Part of the wall of venturitube 70 is cut away at the tube bottom as indicated at 74 to provide alaterally directed opening at the lower end of the venturi tube. Thisend of the venturi tube is partially blocked by a horizontal deflectorplate 76 which is formed with a circular recess 78 through which extendsthe tube 44 for passage of liquid from the container to the mixingchamber 40. As can be seen in FIG. 3, tube 44 is offset slightly to theside of the nozzle orifice 36 so that the gas stream projected atincreased velocity from the nozzle orifice and along the venturi tubeaxis will travel downwardly, expanding as it travels to partly impingeupon an upper curved and tapered entrance portion 80 of the venturitube. The high velocity jet mixture is funneled by the venturi tubedownwardly to its open end to impinge upon deflector 76 which redirectsthe jet stream outwardly from a point within the container at its upperportion to impinge upon the inner surface 86 of the container wall at anangle to the surface of this wall. The angular impingement of theredirected mixture upon the container wall again deflects the projectedstream, redirecting the stream to flow circumferentially, in a generallyhorizontal plane, around the interior surface of the container 12 in thedirections indicated by arrows 88 (FIG. 2).

The upper portion of container 12 between the lid and the upper surfaceof the liquid 16 defines a swirl chamber 90 into which the moistureentraining high velocity stream of oxygen enriched air is projected. Themixture is projected outwardly from a point within the swirl chamber andcaused to flow in the described circumferential and substantiallyhorizontal path. The mixture may begin to descend along the containerwalls in a downwardly spiral path as it swirls around the walls. Fixedto the inner surface of container wall 12 is a plurality ofcircumferentially spaced baffles 92, 94, 96 and 98 each of which extendsvertically along the container sides. The baffles, in effect, formstiffening ribs for the container wall, but, because of their verticalextent across the horizontal direction of swirling mixture flow,primarily provide limited obstructions or obstacles to thecircumferential flow of the mixture. Large water droplets entrained inthe swirling gas mixture impinge upon the baffles in the course of theswirling flow of the mixture and are trapped, thereby to be removed fromthe swirling mixture and to flow downwardly along the container sidesinto the body of water within the container. The pressurized swirlingmixture from the chamber 90 flows outwardly to be discharged from thecontainer through discharge conduit 64.

An unexpectedly improved operation is achieved by the introduction ofcompressed air into mixing chamber 40. Fitting 54 directs a stream ofcompressed air horizontally into the mixing chamber and againstdeflector 46 which has a deflecting surface of web 52 curved in acircular arc, in a horizontal plane, as best seen in FIG. 2. Thecompressed air is redirected downwardly by the deflector, which, byvirtue of the larger side wall 48, causes the downwardly deflectedcompressed air stream to flow almost entirely to one side of thedeflector (toward the lower part of the drawing in FIG. 2). Thecompressed air stream is caused to flow toward the entrance surface ofthe venturi tube, with a slight swirling action which imparts to the gasa somewhat spiral, downward flow, tending to move around the mixingchamber in a clockwise direction as viewed in FIG. 2. This compressedair stream is substantially parallel to the oxygen stream from jetnozzle 36, but is transversely offset from the venturi tube axis so asto impinge upon the curved entrance surface 80 of the venturi tube andgenerate an increased turbulence in the mixing chamber 40. In thearrangement described herein the venturi tube 70 is fixed at a lowerposition with tubular mixer body as compared with the arrangement of myprior co-pending application, so as to provide a greater distance forthe downwardly directed side by side flow of the moisture entrainingoxygen stream and the compressed air stream.

The combined action of the liquid-entraining oxygen jet and theseparately admitted jet of compressed air, which flows downwardly to theventuri tube alongside the oxygen jet, provides several surprising andunexpected improvements. It is found that entrainment of water in thedischarged mixture is much greater with the described arrangement thanin various arrangements of the prior art, and greater than in theapparatus described in the above-mentioned co-pending application. Thereis substantially less water drop out in the exit tubing, connecting thenebulizer to the patient, with the arrangement described herein. Thissignificant improvement has been shown by comparative tests. In theprior arrangement of my copending application, 12% of the total waterused (from the interior of the container) is found to collect in thetubing to the patient. With the arrangement described herein, on theother hand, where a separate compressed air input is provided, it isfound that only 21/2% of total water used collects in the output tubing.This is evidence of the significantly improved efficiency of moistureentrainment and of the desired increase in water content of the airsupplied to the patient.

Another unexpected and surprising result derived in the operation of theinvention described herein is that variation in back pressure does notsignificantly affect the percentage of oxygen in the output mixture.Further, the described arrangement enables independent control of theamount of water in the output mixture and the percentage of oxygen inthe output mixture. The amount of water in the output mixture iscontrolled by control of the oxygen flow rate, which in turn controlswater aspiration. The percentage of oxygen in the output mixture iscontrolled by varying flow rate of compressed air fed through the secondinput fitting 54. Still further, the amount of oxygen in the output canbe controlled down to a small percentage, well below 28%, withoutexpensive regulating valves or complex equipment. It is merely necessaryto set the desired oxygen input flow rate at the desired level, such as,for example, five liters per minute, and then to open up a valve (notshown) on the input line 56 to the compressed air input fitting 54,thereby increasing air input and decreasing output oxygen percentage. Inthis connection, it may be noted that many hospital rooms are providedwith fixtures on the wall from which are available hospital providedsupplies of both oxygen and compressed air. Accordingly, it is a simpletask to employ the nebulizer described herein, since one has only toconnect suitable tubing between the oxygen and air input fittings of thenebulier and the output wall fittings of the hospital room.

Using a separate source of compressed air, an increased restriction orincreased back pressure down not increase the percentage of oxygen inthe output. Having a relatively large fixed pressure air supply fed tothe compressed air input fitting 54, the percentage of oxygen in theoutput is independent of change in back pressure, so that when backpressure is increased, as by connection of the patient and/or tubing tothe nebulizer, the percentage of oxygen in the output does not change.The compressed air may be fed to the input fitting 54 through a suitablefilter or filters (not shown), as desired.

In the arrangement of my prior co-pending application, larger waterparticles forming in the mixing chamber fall downwardly into the chamber90 of the container. With the present arrangement, on the other hand,such large particles are blown downwardly against the entrance surfaceof the venturi tube. These larger particles collect and are temporarilytrapped on the entrance surface of the venturi tube, forming a body ofexceedingly turbulent, "standing" water having a configuration asgenerally indicated in the schematic drawings of FIGS. 5 and 6. Thus, anarea 120 is indicated in the horizontal sectional view of FIG. 6 as thecenter of impingement of the downwardly-directed compressed air streamupon the tapered entrance surface of the venturi tube. This center ofimpingement is laterally offset because of the configuration ofdeflector 46. Turbulence of the swirling air, oxygen and water mixturein the mixing chamber is greatly increased by the impingement of thecompressed air jet upon the venturi tube entrance surface 80. Over acircumferential area of the venturi entrance surface extending in aclockwise direction from point 122 to point 124 there is relativelylittle "standing" water on the entrance surface. From point 124clockwise toward point 122 there is built up around the interior of thetubular wall 22 a wall of turbulent "standing" water, generallyindicated at 126, which has a height that increases from point 124toward point 122. This wall of water is blown by the downwardly directedand somewhat skewed compressed air in a clockwise direction (as viewedin FIG. 6) and also upwardly along the wall 22 to a maximum height at apoint, such as indicated at 128, where the wall of water appears to fallback downwardly upon itself. Thus, the compressed air jet creates andmaintains a wall of turbulent water extending around a major part of thedownwardly-projected oxygen jet, which wall of water, it is postulated,collects and holds larger water particles that tend to drop out of thehigh velocity oxygen stream and are too large to be fully entrapped inthe oxygen stream.

As shown in FIGS. 2 and 7, a detachable and disposable heater adapter100 has an input fitting 102 connected to output leg 66 of the dischargeconduit 64 and has a heater output fitting 104. The heater adapterincludes an intermediate enlarged body portion 106 forming an enlargedheater chamber 108 between the input and output fittings 102, 104. Acylindrical heater element 110, mounted to the heater adapter body,extends through an aperture 112 in the enlarged heater section 106 andterminates in an electrical connector 114 to which may be connectedsuitable power wires for the heater element and sensing wires for athermocouple contained within the heater element 110. An annular heaterbaffle 119 projects radially inwardly from the interior surface ofheater input fitting 102 at the junction of this fitting with theintermediate heater section 106. Heater chamber 108 has an increaseddiameter, being larger in cross-sectional area than the cross-sectionalarea of the input of the heater input fitting 102, and therefore, largerthan the area of the passage through the heater baffle 120.

The illustrated heater configuration acts to further entrap waterdroplets and remove such large water droplets from the inhalationmixture. Baffle 120 acts to decrease the passage area, thus increasingits velocity. The baffle causes further entrapment of relatively largewater particles which may then flow into the enlarged heater chamber108. The flowing mixture passing through the enlarged heater chamber 108decreases in velocity, thus providng a greater time for the desired heatexchange between the heater element and the mixture. In addition, theheater element raises the temperature of water that may collect in thebottom of the heater chamber, thus vaporizing water in the bottom of theheater chamber which then is again entrained as the desirably smallsized droplets or vapor within the flowing mixture. The moisturizedmixture having been heated in the heater chamber and further cleansed oflarger water droplets, now may flow through the heater output fitting104 and thence through an inhalation conduit (not shown) attached to thefitting 104 and connected to suitable breathing apparatus of the subjectof the inhalation therapy.

Another unusual, surprising, and unexpected advantage of the describedconfiguration is its quiet operation. Prior art nebulizers generate asignificant amount of sound, which appears to emanate from the dischargetube. A large amount of noise also comes from the air entrainment ports(omitted in the configuration disclosed herein) of prior nebulizers, andthus increases background sound level in the area around priornebulizers. Discharge tube sound is transmitted through the conduitconnecting to the patient. It is found that the operation of thenebulizer described herein is as much as 50% quieter than commonly usedprior art nebulizers. It is postulated that the significant decrease innoise of operation is due to the discharge of the liquid entrainingmixture into the relatively large swirling chamber 90 and the structureof the nebulizer which directs this discharge into a relatively largediameter swirling path. Absence of open air entrance ports alsocontributes to the decrease in generated noise.

Preferably the container 10 is made as a one-piece molded vessel withthe baffles 92 through 98 being tapered as illustrated in FIG. 3 solelyfor ease of molding. Lid 18 together with mixer body 20 are also moldedas a single integral unit to which is then affixed to the jet nozzle 34and deflector 46, the aspirator 42 and tube 44 connected between theaspirator and the container bottom. All parts are sterilized. Sterilewater is introduced into the container to a suitable level below thecontainer top (which may be one or two inches below the top) for anexemplary container that may be six inches from lid to bottom and threeand a half inches in diameter at its lid.

There has been described an improved nebulizer employing a high-velocityoxygen stream that aspirates water for moisturization of the output, inwhich efficiency of water entrainment is significantly improved, inwhich the range of oxygen content of the output is extended downwardly,and in which a selected oxygen content of the output at a given inputflow rate of oxygen can be maintained by independent adjustment ofcompressed air input. The arrangement provides a significant improvementby providing an increased moisture content of the output mixture and asignificantly decreased amount of waste water.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

I claim:
 1. A nebulizer for inhalation therapy comprising a mixerhousing having a mixing chamber therein with an open end, said housinghaving first and second input ports,a venturi tube mounted in said openend, said venturi tube including an input end having an entrance surfacetapering inwardly toward the axis of said tube and toward said open end,nozzle means in said chamber connected to said first port for projectinga first stream of high velocity oxygen from said first port along afirst axis in said chamber, an aspirating conduit having an end in saidchamber adjacent said nozzle means and adapted to be connected to a bodyof liquid for flowing liquid to said first stream at a point adjacentsaid nozzle means, thereby entraining liquid in said first stream, meansfor projecting a second stream of compressed air into said chamber inproximate relation to said nozzle means, deflector means in the path ofsaid second stream and being configured and arranged for deflecting saidsecond stream in a downwardly swirling path toward said entrance surfacein a direction substantially parallel to said first stream and along asecond axis adjacent the axis of said first stream, whereby said firstand second streams are mixed with fluid in said chamber to provide amoisturized oxygen enriched air mixture, and, means for discharging saidmoisturized mixture from said chamber,said deflector means beingoriented to direct said second stream along an axis intersecting saidentrance surface of the venturi tube, said deflector means including aninput fitting for said second stream having an axis transverse to saidfirst mentioned axis, and means on said deflector means for redirectingair from said input fitting, said deflector means comprising achannel-shaped member having a web in proximate relation to said nozzlemeans and first and second side walls, said web and side walls beingconfigured to redirect said second stream in said downwardly swirlingpath toward said entrance surface.
 2. A nebulizer for inhalation therapycomprisinga mixer housing having a mixing chamber therein, said mixerhousing comprising a hollow body open at one end, and having first andsecond input ports, nozzle means in said chamber connected to said firstport for projecting a first stream of high velocity oxygen from saidfirst port along a first axis in said chamber, an aspirating conduithaving an end in said chamber adjacent said nozzle means and adapted tobe connected to a body of liquid for flowing liquid to said first streamat a point adjacent said nozzle means, thereby entraining liquid in saidfirst stream, means for projecting a second stream of air in saidchamber in a direction substantially parallel to said first stream andalong a second axis adjacent the axis of said first stream, said meansfor projecting said second stream comprising a deflector on said nozzlemeans, an input fitting for said second stream having an axis transverseto said first-mentioned axis, and means on said deflector forredirecting air from said input fitting, said deflector comprising achannel-shaped member having a web fixed to said nozzle means and firstand second side walls, and wherein said first and second streams areintroduced to said chamber at points that are displaced from said oneend, said first and second streams being directed to flow toward saidone end, whereby said first and second streams are mixed with liquid insaid chamber to provide a moisturized oxygen enriched air mixture, andmeans including a venturi tube mounted in said one end of the chamberfor discharging said moisturized mixture from said chamber, said venturitube including an input end having an entrance surface tapering inwardlytoward the axis of said tube and toward said one end of said housing,said web and side walls of said deflector being configured to redirectsaid second stream in a downwardly swirling path toward said entrancesurface, and wherein said second stream is directed along an axisintersecting said entrance surface.
 3. A nebulizer for producing amixture of oxygen enriched air and liquid for inhalation therapycomprisinga container confining a body of liquid, a mixer body mountedto the container and comprisinga mixer housing defining a mixingchamber, said mixer housing comprising a hollow body open at one end, aventuri tube mounted in said one end, said venturi tube including aninput end having an entrance surface tapering inwardly toward the axisof said tube and toward said one end of said housing, nozzle means insaid housing for projecting a first stream of gas at a high velocityalong a first axis through said chamber, through said venturi tube andinto said container, said first stream being introduced to said chamberat a point displaced from said one end and directed to flow toward saidone end, aspirating means connected between a lower portion of saidcontainer and a point adjacent said nozzle means for flowing liquid fromsaid container to said high velocity stream within said chamber, secondgas input means for projecting a second stream of a second gas into saidchamber along an axis transverse to said first axis, said second streambeing introduced to said chamber at a point displaced from said one end,and deflector means in proximate relation to said second gas inputmeans, said deflector means comprising a channel-shaped member having aweb adjacent to said nozzle means and first and second side walls, saidweb and side walls being configured to redirect said second stream alonga path generally parallel and in proximate relation to said first axisand in a downwardly swirling path toward said entrance surface, forproducing a stream through said venturi tube comprising a moisturizedmixture of liquid and said first and second gases.
 4. A nebulizer forinhalation therapy comprisinga mixer housing having a mixing chambertherein, said mixer housing comprising a hollow body open at one end, aventuri tube mounted in said one end, said venturi tube including aninput end having an entrance surface tapering inwardly toward the axisof said tube and toward said one end of said housing, nozzle means insaid housing for projecting a first stream of gas at a high velocityalong a first axis through said chamber, through said venturi tube andinto said container, said first stream being introduced to said chamberat a point displaced from said one end and directed to flow toward saidone end, aspirating means connected between a lower portion of saidcontainer and a point adjacent said nozzle means for flowing liquid fromsaid container to said high velocity stream within said chamber, secondgas input means for projecting a second stream of a second gas into saidchamber along an axis transverse to said first axis, and second streambeing introduced into said chamber at a point displaced from said oneend, and deflector means in proximate relation to said second gas inputmeans, said deflector means comprising a channel-shaped member having aweb adjacent to said nozzle means and first and second side walls, saidweb and side walls being configured to redirect said second stream alonga path generally parallel and in proximate relation to said first axisand in a downwardly swirling path toward said entrance surface, forproducing a stream through said venturi tube comprising a moisturizedmixture of liquid and said first and second gases.